Testing ignition coils with a volt/ohm meter

[Warped_1966]

I need to know what the resistance should be on my 2002 Echo's coils. I have an intermittent sputtering problem and it's driving me nuts! I put E3 spark plugs in the car about a year ago to help improve the power and economy (it was on the original plugs at 160k miles!!) and they did help a lot but not long after that the sputtering problem started.

The car does have a code for the pre-converter O2 sensor but I replaced it, cleared the code and it keeps coming back. I have not pulled the codes recently but will in the next few days.

I've also read that the fuel filter is inside the gas tank but there is an access port under the back seat. I doubt that would cause the intermittent problem but I could be wrong. Thoughts?

Thanks in advance for any help!

[ericlp]

https://docs.google.com/viewer?a=v&q...1ADG4IOia9LbNg

not sure but the service manual doesn't even show the resistance. I would imagine if checked all four and they all had the same resistance than you'd be good to go?

Good Luck! I could only find this google doc to a link for the manual. They use to have tons on them online now only this.

[Warped_1966]

Thanks ericlp. I checked the coils every conceivable way with an ohm meter and compared them to one of my girlfriend's known good coils. The results are that two of them are bad... :-\

[ericlp]

Hmm, if you had two bad coils I would think your could not start your car. But... If I were you before buying two of them (kinda expensive) Just buy one of them and swap that one with the two you think are bad. It's possible to have two bad coils but well, I'd think your car would be in really bad condition. Tho, I don't know maybe your coils are just working part of the time? I'd also think that if there were to test the resistance on a coil they would have that step in the shop manual. Kinda makes me think they have different coils that can have different values. So.... Either buy where you can take them back for a refund or just buy one and try that.

BTW, what where the values you recorded for good vs bad?

Thanks! If you fix your problem this might help others.

Edit: I guess 30 bucks isn't that bad for coil packs. Thought they were around 100 bucks a pop.

[Warped_1966]

ericlp,

The car was still running ok most of the time, it would occasionally sputter on acceleration either from a standing start or while moving. It was totally random. Maybe saying "bad" coils wasn't the right term. I think they were internally shorted because they had less resistance than known good coils when reading through them.

I ordered new coils through rockauto.com and installed them and that particular issue is resolved. The car still gives a little hiccup here and there under acceleration though.